Key Takeaways & Executive Findings
- •• • The rod-shaped bismuth-based electrode achieved a detection limit of 0.34 μg·L−1 for Pb(II), which is below the WHO guideline of 10 μg·L−1 for drinking water, enabling trace-level monitoring. • • Sensitivity was measured at 106 μA·(μmol·L−1)−1, indicating high electrochemical activity and strong signal response, facilitating accurate quantification in low-concentration ranges. • • The linear detection range spans 1–90 μg·L−1, covering typical contamination levels in environmental waters, thus suitable for routine screening. • • The sensor demonstrated high recovery rates in real water samples (tap water and campus lake water), confirming its reliability and potential for on-site monitoring in public swimming pools.
Abstract
This study presents a novel electrochemical sensor for the rapid detection of trace lead ions (Pb(II)) in water, utilizing a rod-shaped bismuth-based electrode. The electrode was fabricated by modifying a glassy carbon electrode (GCE) with basic bismuth nitrate [Bi6O5(OH)3](NO3)5·3H2O, synthesized via a chemical precipitation method. The sensor was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), electron probe microanalysis (EPMA), and energy-dispersive X-ray spectroscopy (EDS), confirming the rod-like morphology and composition. Electrochemical detection was performed using differential pulse voltammetry (DPV) in a 0.1 mol·L−1 NaAc-HAc buffer (pH 4.3). The sensor exhibited a linear detection range for Pb(II) from 1 to 90 μg·L−1, with a detection limit of 0.34 μg·L−1 and a sensitivity of 106 μA·(μmol·L−1)−1. The electrode demonstrated excellent anti-interference capability and reproducibility. Recovery tests in real water samples (tap water and campus lake water) yielded high recovery rates, indicating practical applicability. This work provides a simple, cost-effective, and reliable method for monitoring trace Pb(II) in environmental water, particularly relevant for public swimming pools and similar aquatic facilities.
1. Introduction
Heavy metal contamination in water bodies poses a significant threat to public health and ecological systems. Lead (Pb) is particularly hazardous, as it can accumulate in the human body and cause severe damage to the nervous, hematopoietic, and reproductive systems. Traditional detection methods, such as inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectroscopy (AAS), offer high sensitivity but are often labor-intensive, time-consuming, and unsuitable for on-site monitoring. This limitation is critical in scenarios like swimming pools and sports facilities, where rapid and frequent water quality assessment is essential to safeguard athlete health.
Electrochemical sensors have emerged as promising alternatives due to their high sensitivity, low cost, and portability. Bismuth-based materials, especially basic bismuth nitrate, have gained attention for their low toxicity and excellent electrochemical properties. However, conventional powder forms suffer from agglomeration and low active site utilization, hindering their performance. This study addresses these bottlenecks by engineering a rod-shaped morphology of [Bi6O5(OH)3](NO3)5·3H2O, which provides a high surface area and efficient electron transfer. Additionally, a Nafion membrane coating enhances selectivity and anti-interference capability. The developed sensor demonstrates a low detection limit and high sensitivity, offering a practical solution for trace Pb(II) monitoring in environmental and recreational waters.
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WANG Chencan, YANG Yuxi, WAN Junfeng, GUO Xiaoying, XU Zicong, YANG Jinghe, ZHANG Jie, JU (2026). Rapid Detection of Trace Pb(II) in Water Using a Rod-Shaped Bismuth-Based Electrode. Chinese Journal of Environmental Engineering. https://doi.org/10.12030/j.cjee.202507057
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Frequently Asked Questions
What is the operational lifetime or stability of the rod-shaped bismuth-based electrode under repeated use?
The study reports good reproducibility, but specific data on long-term stability or electrode lifetime is not provided. Typically, bismuth-based electrodes can maintain performance over multiple cycles if stored properly. Further testing would be required to quantify the number of usable cycles before signal degradation.
How does the sensor perform in the presence of common interfering ions such as Cd(II), Cu(II), or Fe(III)?
The study claims good anti-interference capability, but specific interference data is not detailed. The Nafion membrane is designed to selectively attract Pb(II) via electrostatic interactions, which may reduce interference from other cations. However, quantitative data on the tolerance limits for each interfering ion would be necessary for a comprehensive assessment.
What is the cost per test compared to conventional methods like ICP-MS?
The materials used (bismuth nitrate, Nafion, and glassy carbon electrodes) are relatively inexpensive, and the fabrication process is simple. This suggests a significantly lower cost per test compared to ICP-MS, which requires expensive instrumentation and skilled personnel. However, a detailed cost analysis is not provided in the paper.
Can the electrode be scaled up for mass production and field deployment?
The fabrication process is straightforward and uses readily available materials, making it amenable to scale-up. However, challenges such as batch-to-batch reproducibility and electrode-to-electrode consistency need to be addressed. The use of glassy carbon electrodes may also be a limiting factor for disposable applications, but alternative substrates could be explored.
What is the response time of the sensor for a single measurement?
The DPV parameters include a pulse period of 0.2 s and a quiet time of 10 s, suggesting that a single measurement could be completed within a few minutes. However, the exact total time from sample addition to result is not explicitly stated. This rapid response is advantageous for on-site monitoring.
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